Rewrite ${((7^{-3})(5^{7}))^{-7}}$ in the form ${7^n \times 5^m}$.
Answer: ${ ((7^{-3})(5^{7}))^{-7} = (7^{(-3)(-7)})(5^{(7)(-7)})} $ ${\hphantom{ ((7^{-3})(5^{7}))^{-7}} = 7^{21} \times 5^{-49}} $